降雨型滴谱与反射率因子及雨强关系研究

利用C＋＋Builder对激光降水粒子谱仪的原始雨滴谱数据进行解码,应用M-P分布对2008年6月8—9日庐山的一次降雨过程进行拟合。结果表明,M-P分布的拟合曲线与雨强有关,但不利于对比分析雨滴谱。以无量纲粒子直径和无量纲粒子密度分布的自然对数为自变量和因变量,建立M-P分布、线性最小二乘拟合、Γ分布的雨滴谱拟合关系式,通过误差分析得到Γ分布相对最优。比较雨滴谱反演的回波强度和南昌雷达观测取样点上的回波强度,发现它们随时间的变化趋势大体一致,但反演的回波强度略大于雷达观测。按平均直径、中数体积直径对降雨进行分类,分别建立层状云和对流云降雨的反射率因子和雨强之间的关系式（Z-I关系式）,2种降雨类型关系式的系数存在明显的不同。

RAINDROP SIZE DISTRIBUTION AND THE RELATIONSHIP BETWEEN RAINFALL RATE AND REFLECTIVITY

The raindrop size distribution data is decoded with C＋＋ BUILDER program and the M-P distribution method is used to fit the relationship between rainfall rate and reflectivity for the June 8-9, 2008 rain process in Lushan. The results show that the M-P distribution is related to rainfall rate, and it is not suitable for the contrastive analysis of raindrop size distribution. Therefore, the relationships between the normalized diameter and natural logarithm of normalized number density are found based on M-P distribution, linear least squares fit, Gamma distribution. The analyses of squared error show that Gamma distribution is the best. The comparison of echo intensity derived from raindrop size distribution with that from Nanchang radar observation reveals that they vary coincidentally, and the intensity retrieved from raindrop size distribution is slightly larger than that from radar observations. The mean diameter and the median volume diameter are used to classify the precipitation process, and the Z-I relationships between reflectivity and rainfall rate are established for convective cloud rainfall and stratiform cloud rainfall and their coefficients are significantly different.